1. Technical Field
The present disclosure relates to a power converter. More particularly, the present disclosure relates to voltage regulation of a power converter.
2. Description of Related Art
As energy demand increases significantly nowadays, renewable energy generation, such as wind power, fuel cell, solar cells (i.e., photovoltaic cells, PV), etc., becomes more and more attractive. In such application, power conversion with high efficiency, high power density, high reliability and low cost is normally required, particularly for the energy applications with wide range.
Typically, a power converter with high efficiency is provided in the aforementioned power conversion applications and the power converter is usually operated with high switching frequecy under a certain condition. Moreover, soft switching for switch devices in the power converter is performed, and thus high reliability of the power converter can be achieved as well. Resonant converter, such as LLC converter, is one of them which has been widely used.
However, with LLC converter, under the condition that the power converter is operated with frequency modulation, a wide range of switching frequency is necessary when voltage regulation for a wide range of input voltage inputted into the power converter is required, and this results in complex and difficult circuitry design in the power converter. High conversion efficiency is also hard to be guaranteed with a wide range of switching frequency. In other words, the voltage regulation for a wider range of input voltage inputted into the power converter cannot be achieved if the range of switching frequency is not further extended.